mp9001 backgrounding

[acsolutions]

Hello,
my mp9001 backgrounds badly print and copy, even in the void areas. there is also ghosting, checked the cleaning section ok. any suggestions. Thanks

[rsyarcia]

you should consider checking the drum life. how many copies made?

[teebee1234]

you should consider checking the drum life. how many copies made?

Yes, we need more particulars. Is it OEM toner? Could also be a bias short, erase lamps not functioning or a number of other things.

[acsolutions]

Sorry, the machine has 170,000 on machine, customer just added new toner when the problem occurred. Did a developer change, no change. Check the machines red erase led's ok, checked while machine was running. that was pretty much all I have done. there is no errors, I did not have a chance to pull the cleaning area apart because of the time, did not start the call till 4:30 and got out of their at 5:15. Thanks

[Tonerbomb]

Is it OEM toner and developer??? What is Vref, Vt, and Vcont ?? HWat is the bias voltage set to ?

[acsolutions]

Is it OEM toner and developer??? What is Vref, Vt, and Vcont ?? HWat is the bias voltage set to ?

what are the ref. numbers usually at and if there off what should I be looking at? The toner and developer is OEM. Thanks

[Shadow1]

That sounds suspiciously like a bad drum ground.

[acsolutions]

That sounds suspiciously like a bad drum ground.

Where exactly is the drum grounded? I also noticed that the transfer belt had a film of toner. thanks for the reply

[fbkhan3]

Charge,bias or ground, even a moist Toner could be the cause.if you could attach the specimen it would make it allot easier.

[Shadow1]

Where exactly is the drum grounded? I also noticed that the transfer belt had a film of toner. thanks for the reply

Unless they've seriously changed something from the MP6000 and company the drum ground connects to the developer bias board. At some point during process control they switch developer bias into the drum to calibrate the Drum Potential Sensor. IIRC because of that you can't just test from the drum shell to a ground point. You have to test from the drum shell to the ground lead on the HV Power supply. If the drum ground is bad the drum shaft assembly has to be replaced. You can also have a bad ground relay on the HV board.

Characteristic of a bad drum ground on Ricoh machines is background over everything, very weak solids, and halos around whatever is printed on the sheet. The effect may fade in and out as the drum rotates and grounding through the drum bearings gets better and worse.